Is your 15-month-old suddenly not sleeping through the night, waking up screaming, or refusing naps? You’re not alone.
You’re likely facing the 15-month sleep regression — a developmental phase that almost every toddler (and parent!) endures. Sleep regression can occur at different ages and which causes baby sleep to take a turn.
In this complete 2025 guide, you’ll learn what causes the 15-month sleep regression, the signs to watch for, expert-approved strategies to handle it, and how to get your 15-month-old back to sleeping soundly, day and night.
Table of Contents
What Is the 15-Month Sleep Regression?
The 15-month sleep regression is a temporary but often intense phase in which a toddler’s sleep patterns suddenly worsen.
Your 15-month-old, who may have been sleeping through the night, now wakes multiple times, fights naps, or resists bedtime altogether.
Why it Happens:
At around 15 months, toddlers are going through enormous developmental leaps—physically, cognitively, and emotionally. Their growing brains struggle to shut off at night, causing restless Sleep.
Sleep Expert Tip:
“Developmental progress can temporarily disrupt a toddler’s ability to self-soothe at night,” says Dr. Heather Irvine, pediatric sleep specialist.
Common Developmental Changes at 15 Months:
- Learning to walk independently
- Expanding vocabulary
- Recognizing emotional cues
- Experiencing stronger separation anxiety
🔗 Related Read: Toddler Brain Development and Sleep Patterns Explained
Why Is My 15-Month-Old Not Sleeping?
If you find yourself searching “Why is my 15-month-old not sleeping?” — you’re definitely not alone. Many parents face sleep disruptions during this stage. Here’s a closer look at the major reasons behind the 15-month sleep regression:
1. Major Cognitive Leaps
At 15 months, your toddler’s brain is growing at an incredible pace. They’re learning new skills like recognizing faces, understanding daily routines, and grasping cause-and-effect relationships. However, this cognitive surge means their minds often stay active at night, making it harder for them to wind down and stay asleep.
Pro Tip:
Incorporate calming bedtime stories focused on routine and familiarity, such as Goodnight Moon or Time for Bed. These stories can help reduce mental overstimulation and ease your 15-month-old into restful sleep.
2. Motor Skill Explosions
Your 15-month-old is mastering major physical milestones like walking, climbing, and even running. These new skills excite them — sometimes too much! Even though they might be physically tired, the excitement of mastering movement can cause restless nights and fragmented sleep patterns, a hallmark of the 15-month sleep regression.
Real World Tip:
After periods of energetic play, wind down with quieter activities such as simple puzzles or reading to help your toddler transition smoothly into sleep.
3. Emotional Development and Separation Anxiety
Another major reason your 15-month-old is not sleeping well is emotional development, especially separation anxiety. At this age, toddlers begin to understand that parents can leave — and it can feel overwhelming for them, especially at bedtime.
Help Your Toddler Feel Secure By:
- Establishing a consistent, comforting bedtime phrase, like “I’ll see you after you sleep.”
- Offering a special transitional object, such as a beloved stuffed animal or a soft security blanket, to provide emotional reassurance throughout the night.
4. Nap Transitioning
Many toddlers around 15 months are beginning to shift from two naps a day to one. This nap transition can seriously disrupt nighttime sleep if schedules aren’t adjusted accordingly.
Signs Your Toddler Might Be Ready for a Nap Transition:
- Consistently refusing the second nap.
- Taking much longer to fall asleep at nap times.
- Sleeping longer stretches at night without needing two daytime naps.
If your 15-month-old is not sleeping well and also fighting naps, it may be time to modify their daytime sleep schedule.
5. Teething and Molars
Teething — especially the painful arrival of molars — is a very common culprit when your 15-month-old is not sleeping. Gum discomfort can cause frequent night wakings, irritability, and trouble settling back to sleep.
Teething Comfort Checklist:
- Provide cold teething rings for safe chewing relief.
- Offer a chilled, clean washcloth for your toddler to bite on.
- Consult your pediatrician about safe, approved pain relief methods if discomfort becomes intense.
Summary:
If your 15-month-old is suddenly not sleeping, waking up crying at night, or struggling with naps, it’s very likely linked to the natural 15-month sleep regression. Cognitive growth, motor skill surges, emotional changes, nap transitions, and teething all contribute to disrupted sleep during this time. By understanding these developmental challenges and applying supportive strategies, you can help your toddler — and yourself — get back to more peaceful nights.
15-Month Sleep Regression Signs to Watch For
I’m not. Is it the 15-month regression? Watch for these signs:
- Night wakings every 1–2 hours
- Bedtime protests or screaming fits
- Shortened naps (30 minutes or less)
- Early morning wakeups (before 6 a.m.)
- Sudden extreme clinginess
- Nighttime fears (darkness, being alone)
Parent Insight:
“My daughter used to sleep 11 hours straight. Suddenly, at 15 months, she woke up four times a night needing cuddles.” — Kelly, mom of two.
How Long Does the 15-Month Sleep Regression Last?
The good news:
Most 15-month sleep regressions last between 2 and 6 weeks if handled consistently.
Timeline: What You’ll Notice
Week 1: Frequent night wakings begin
Week 2–3 Nap struggles and clinginess peak
Week 4: Gradual improvement with routine consistency
Weeks 5– 6: Sleep returns to normal (or better!)
How to Get a 15-Month-Old to Sleep Through the Night
Ready to reclaim your nights? Follow these strategies:
1. Stick to a Strict Bedtime Routine
Bedtime routines help toddlers predict and prepare for Sleep.
Sample 30-Minute Routine:
- Bath
- Pyjamas
- Two short storybooks
- Singing a lullaby
- Lights out and white noise
2. Set Age-Appropriate Sleep Expectations
At 15 months, toddlers generally need:
- 11–12 hours of nighttime sleep
- 1–2 hours of daytime napping
Practical Tip:
Avoid overtiredness. Put your toddler to bed earlier if naps are short.
3. Allow for Independent Sleep Skills
Support your toddler learning to fall asleep without help:
- Comfort briefly, but leave while they’re drowsy
- Avoid rocking to sleep unless you want to maintain it long-term
4. Manage Middle-of-the-Night Wakeups
Middle of the Night Response:
- Wait 2–5 minutes before entering
- Keep interactions minimal (no lights, no talking)
- Offer a short phrase: “Time for sleep,” then leave
What to Do When a 15-Month-Old Refuses Naps
If your 15-month-old is refusing naps, try:
- Moving nap time later by 15–30 minutes
- Making the room pitch dark
- Using a consistent pre-nap routine
- Offering quiet time if Sleep doesn’t happen (at least 30–45 minutes)
Age-Recommended Wake Windows
Morning 5–6 hours
Post-nap 5–6 hours
Important:
Even one missed nap can cause major overnight sleep disruptions during this regression!
Sample 15-Month Sleep Schedules
Here are two sample schedules depending on whether your toddler is still taking two naps or has transitioned to one:
Option A: Two-Nap Schedule
- Wake: 7:00 a.m.
- Nap 1: 9:30–10:30 AM
- Nap 2: 2:00–3:00 PM
- Bedtime: 7:30 p.m.
Option B: One-Nap Schedule
- Wake: 7:00 a.m.
- Nap: 12:00–2:00 p.m.
- Bedtime: 7:00 p.m.
🔗 Resource: Best Toddler Sleep Schedules by Age
Real-World Parent Success Stories
Case Study: Liam’s 15-Month Sleep Regression
“Liam was up every 90 minutes overnight. We focused on consistent wake times and a soothing bedtime routine. It took 4 weeks, but now he sleeps 11 straight hours.” — Jasmine, mom of Liam.
Case Study: Sofia’s Nap Battles
“Sofia fought naps like crazy at 15 months. Shifting to one nap at noon and keeping bedtime earlier solved it within 10 days.” — Aaron, dad of Sofia.
When to Seek Professional Help
Seek professional help if:
- Sleep issues persist longer than 6–8 weeks
- Your toddler snores heavily (possibly sleep apnea)
- You feel overwhelmed, exhausted, or frustrated
Conclusion: Conquering the 15-Month Sleep Regression
The 15-month sleep regression can be tough, but it’s temporary.
With consistency, patience, and a strong sleep foundation, you and your toddler will likely return to restful nights and enjoy even better sleep habits in the long term.
Key Takeaways:
- Stick to a soothing, predictable bedtime routine
- Support independent sleep skills
- Adjust nap schedules thoughtfully
- Stay consistent and patient — Sleep will come!
FAQs About the 15-Month Sleep Regression
What is the 15-month sleep regression?
The 15-month sleep regression is when toddlers experience sudden sleep disruptions, such as night wakings, nap refusals, or bedtime struggles. This typically happens due to significant developmental changes, including walking, talking, emotional growth, and cognitive leaps. Although exhausting, this regression is entirely standard and usually temporary.
Why is my 15-month-old no longer sleeping through the night?
If your 15-month-old is not sleeping through the night, it could be due to developmental milestones, increased separation anxiety, teething discomfort, or a transition to naps. These changes make it harder for toddlers to fall asleep independently or stay asleep all night, even if they previously had good sleep habits.
How long does the 15-month sleep regression last?
The 15-month sleep regression typically lasts between 2 and 6 weeks. However, the duration can vary depending on how consistently you maintain your sleep routines and whether additional factors, such as teething or illness, are present. Staying patient and consistent helps shorten the length of the regression.
What are the signs of a 15-month sleep regression?
Common signs of a 15-month sleep regression include frequent nighttime wakings, bedtime resistance, shortened or skipped naps, early morning wakeups, and sudden clinginess during the day. These behaviours often happen without signs of illness or significant environmental changes, pointing to developmental reasons behind sleep issues.
How can I get my 15-month-old to sleep through the night again?
To get your 15-month-old to sleep through the night, maintain a consistent bedtime routine, offer comfort without creating new sleep habits, ensure an age-appropriate nap schedule, and manage separation anxiety gently. Using a dark, cool, and calm sleep environment also improves overnight sleep quality.
Is it normal for a 15-month-old to refuse naps?
Yes, it’s normal for a 15-month-old to refuse naps during the 15-month sleep regression. Nap resistance often occurs because toddlers are transitioning from two naps to one or reaching developmental milestones. Stick to a rest schedule even if they don’t sleep.
How do I handle my 15-month-old refusing naps?
When your 15-month-old refuses naps, offer quiet time instead of forcing Sleep. Maintain regular nap opportunities and adjust nap timing gradually. Make the room dark and distraction-free. Consistency is key: even offering quiet rest helps maintain a healthy sleep rhythm during regressions.
Does teething affect the 15-month sleep regression?
Teething can worsen the 15-month sleep regression. The arrival of molars often causes nighttime discomfort, leading to increased waking or difficulty falling asleep. Offering safe teething toys, cold foods, and pediatrician-approved pain relief can help your toddler sleep better during this phase.
Should I sleep train during the 15-month sleep regression?
Gentle sleep training during the 15-month sleep regression can be practical if done carefully. Focus on consistent routines, brief nighttime check-ins, and teaching your toddler to fall asleep independently. Avoid introducing new sleep crutches during the regression to prevent long-term sleep challenges.
When should I seek professional help for toddler sleep issues?
Seek help from a paediatrician or certified sleep consultant if your toddler’s sleep issues persist beyond 6–8 weeks, if they have symptoms like loud snoring or gasping during Sleep, or if sleep deprivation affects their development. Early intervention can make a big difference.
